It has been desired to produce housings of electronic appliances which have a property of shielding electromagnetic waves to reduce electromagnetic interference. To this end, coating with electroconductive paints, attachment of metal flakes and admixtures of conductive agents into moulding materials are known. Among these methods, the last method is believed to be of practical use to attain a high level of electromagnetic shielding effectiveness with ease. As a way of performing this method where an electroconductive agent is admixed into a moulding material, it is known to uniformly mix short metal fibers or metal flakes with thermoplastic resins in a kneader or an extruder, extrude them into pellets and then shape them into an article. Some shielding materials having this configuration are available in the market, for instance, polybutylene terephthalate compounded with 40% by weight by nickel coated mica, and high impact polystyrene compounded with 8 to 16% by weight of stainless steel chopped fibers. However, moulded articles from these materials exhibit a poor volumetric resistivity of the order of 1 ohm cm. Volumetric resistivity is a measure of the shielding effectiveness and is determined in the method which will be stated below. In another manner, a synthetic resin is used to coat the continuous filaments of carbon fibers having metal plating or vapor deposited metal coating on the surface and this is cut into pellets having a desired size (Japanese Patent Application Laying-Open Sho-59-22710/1984). Molded articles produced from this type of pellets containing, for instance, 20% by weight of nickel coated carbon fibers, have an improved volumetric resistivity of the order of 10.sup.-2 ohm cm according to our measurement, but this value is not always satisfactory. Further, conductive material for moulding which contains master pellets and natural pellets, wherein the master pellets contain long stainless steel (SUS 304) fibers in the core and the natural pellets contain no conductive fillers (Japanese Patent Application Laying-Open Sho-61-296066/1986). The above article indicates that a molded article from this material exhibits the highest shielding effect, i.e., 48 dB, at 100 MHz and 16 dB at 1000 MHz. These values are not satisfactory.